A Novel Adaptive Bit and Power Allocation Algorithm with High Efficiency for MIMO-OFDM System

MIMO-OFDM is applied widely as one of the most innovative physical-layer technologies. Adaptive modulation for MIMO system is analyzed in this paper, and a novel adaptive bit and power allocation algorithm for MIMO-OFDM system based on improved antenna subset selection is proposed, which is called ASBPA algorithm and can dynamically select the optimal subset of transmitting antennas. In this paper, Lagrangian multiplier method is utilized to carry out bit and power allocation, and the remaining power is then allocated by greedy principle, the main idea is that, antenna subset selection algorithm can select the special subset which contributes to the channel capacity most for all. Compared with the existing Hughes-Hartogs algorithm, the simulation results show that the proposed adaptive power allocation algorithm can enhance system capacity and reduce bit error rate, achieving the good tradeoff between calculation complexity and system performance.